Conventional nuts and bolts are notoriously well known and are used for an almost limitless variety of applications for joining one structural member to another. Hexagonal nuts are the most common types of nuts, although square and other types are also used. Typically, a nut has internal threads and threads into a bolt having external threads.
For the vast majority of applications, the simple hex nut and bolt combination is perfectly satisfactory. However, some applications call for a relatively long bolt with a relatively large number of threads for the nut to engage and thread over before the nut reaches the end of travel. In such applications, the nut must be turned for an inordinately long period of time before the nut can be tightened. In other applications, the end of the bolt onto which the nut is initially engaged may become damaged through cross-threading, impact damage, corrosion, or other damage. In this case, the nut may not pass over the damaged thread area in order to thread down over the remainder of the bolt.
More et al. in U.S. Pat. No. 6,799,930 taught a quick release nut formed of a pair of body members or segments having internal surfaces to be placed around and engage the shaft of a bolt. The segments were movable between an operative position and an inoperative position in which the segments are spaced further apart. A pin and quick release cartridge on segment slide within corresponding channels in segment, and a pair of ball bearings were released from the groove by pushing the end of pin axially relative to the quick release cartridge. Unfortunately, the segment halves remained coupled together, whether in the operable or inoperable position, and thus if the head of the bolt to which the nut is to be attached is in physical contact with a board or plate through which the bolt extends, then the nut of More et al. cannot be attached.
This drawback in the art was not a problem with the divided nut construction of Shaffrey, U.S. Pat. No. 2,377,581. The divided nut of Shaffrey included two nut halves which were secured in assembly by a pair of double head links. The heads were of a prismatic form, and the key forming element was laterally undercut from each side to provide a connecting or tension link or bar. The heads where then pinned in place. While the divided nut of Shaffrey did not suffer the drawback of More et al., the complex head construction, and the requirement for pins to retain the two halves of the nut together, make this structure impractical as a construction hardware element. The cost and the time required to assemble the nut in situ outweigh any benefit provided by the divided nut.
Thus, there remains a need for a mechanical nut device which quickly attaches and detaches to a threaded member such as a bolt or a threaded rod without the need to thread the nut onto the end of the threaded member. The nut should be separable so that it need not be slid down the entire length of the bolt to which it is to attach, and should be simple and inexpensive, costing little more than a conventional on-piece nut. The present invention is directed to filling this need in the art.